Adapter apparatus for flash firing system

ABSTRACT

An adapter arrangement for use with a photographic flash firing circuit of a variety which monitors and senses the ignition of a flashlamp. Upon a successful such ignition, the firing circuit derives a unique output signal condition which is used for post exposure control purposes. The adapter arrangement permits such a circuit to be utilized for actuating an electronic flash unit or the like in place of typical flashlamps. To carry this out, an impedance having a resistance value closely related to that of an igniting flashlamp is incorporated in operational union with a switching arrangement. In one embodiment this impedance is combined with the winding of a relay. The relay serves to actuate the substitute lighting unit, while the resistive impedance serves to simulate the impedance of the igniting filament of a flashlamp. With the arrangement, therefore, the flash firing circuit is capable of developing a necessary unique output signal.

vUnited States Patent 1191 Ellin et al.

[ ADAPTER APPARATUS FOR FLASH FIRING SYSTEM [75] Inventors: Seymour Ellin; Richard C. Kee,

both of- Chestnut Hill, Mass.

[73] Assignee: Polaroid Corporation, Cambridge,

Mass. [22] Filed: Feb. 5, 1973 [21] Appl. No.: 329,371

Related US. Application Data [63] Continuation-impart of Ser. No, 246,706, April 24,

[52] US. Cl; 354/145, 240/37.l, 315/209 SC [51] Int. Cl. G03b 15/02 [58] Field of Search 240/l .3, 37.1; 315/209 SC, 315/241 P, 241 S; 354/145, 141; 95/148 FLASH' FIRING CIRCUIT 5] Dec. 31, 1974 Attorney, Agent, or Firm-Gerald L. Smith; John W. Ericson 57 i ABSTRACT An adapter arrangement for use with a photographic flash firing'circuit of a variety which monitors'and senses the ignition of a flashlamp. Upon a successful such ignition, the firing circuit derives a unique output signal condition which is used for post exposure control purposes. The adapter arrangement permits such a circuit to be utilized for actuating an electronic flash unit or the like in place of typical flashlamps. To carry this out, an impedance having a resistance value closely related to that of an igniting flashlamp is incorporated in operational union with a switching arrangement. In one embodiment this impedance is combined with the winding of a relay. The relay serves to actuate the substitute lighting unit, while the resistive impedance serves to simulate the impedance of the igniting filament of a flashlamp. With the arrangement, therefore, the flash firing circuit is capable of developing a necessary unique output signal.

20 Claims, 7 Drawing Figures ELECTRON |c FLASH PIITENTEU D533 1 SHEET 10F 4 I 22 28 2s 30 (I2 N LIGHT 2 Z ELECTRO- SENSITIVE k EXPOSURE CONTROL TRIGGER QQTEP MECHANISM CIRCUIT I I I -24 54 l I 6 FIXED 52 INHIBIT DELAY I I l I ,50 A 48 I l 1 4e CYCLE hi FLASH FLASH [CONTROL V FOCUS FIRING LAMP I8 2 ACTUATOR 2 CIRCUIT ARRAY as 322 2; I

M a 60b 60c 74\ v 62b 62C POWER 640/ 64c SUPPLY 7 760 2 76b Z 76 Z FLASH PULSE LAMP I 78c GENERATOR SWITCHING I v 8O 72 FIG.2

- 4.m mm 3.858.227

sumecm I4 I06 FOLLOW- O ocus ACTUATOR 34 92 T0 FIXED DELAY 52 AND mman FUNCTION n2 60o I 60b 5 I 64b 62b 64c I28 76b 76c SEQUENCE SEQUENCE LOGIC F LOGIC mmau'wm MM 3" 858,227

SHEET-.3 BFv 4' ELECTRONIC I86 I947 J FLASH L FLASH FIRING I90 CIRCUIT V228 2&242 4 40 am 234 ii: 224 228 L Q7 an FLASH 2m FIRING 238 226 cmcun y z I ELECTRONIC FLASH PATENTEDBEM 1 i974 sum u or 4 ELECTRON IC FLASH ADAPTER APPARATUS FOR FLASH FIRING SYSTEM RELATED APPLICATION BACKGROUND OF THE INVENTION In a copending application for United States patent, entitled, Flash Photographic Control System by J. P. Burgarella, P. P. Carcia and R. C. Kee, Ser. No. 246,891, filed Apr. 24, 1972, and assigned in common herewith, a photographic camera is described which not only is fully automated, but also is thin and compact to an extent permitting it to be conveniently carried in the pocket of a garment. Full automaticity for the device is provided from such features as a dual parameter exposure control mechanism, a modified form of reflex viewing and focusing, automatic film processing following each exposure and automatic motorized conversion of components. This conversion moves the components from an initial standby viewing mode to a film unit exposure mode orientation, then returns them to the initial standby viewing mode orientation. These conjunction with an electronic flash illumination source. When the camera incorporates a pulse actuated sequencing and firing circuit suited for flashlamps as described, such a light source substitution is not readily available. For instance, the earlier described monitoring feature of the circuit deriving the noted unique output signal condition requires that the light source assume a particular state when ignited. The normal condition of an electronic flash unit during ignition is much operational functions establish a photographic cycle.

which is carried out in rapid order following the simple depression of a start button located on the camera housing.

To permit more rapid sequential cycling using flash illumination, the camera is designed to operate with a multilamp array of flashlamps, the flashlamps within which are packaged in a linear fashion, all being simultaneously oriented for subject illumination. To ignite select ones of these flashlamps in a predetermined order from first to last, an electronic firing circuit is incorporated within the camera. Typical ones of such sequencing circuits are described in a US. Pat. No. 3,618,492 by S. Ellin. However, as described in the above-referenced application for United States patent, in one preferred embodiment of such circuits, the successful firing of a flashlamp is monitored to derive a unique circuit output signal condition. This unique sigthe camera to provide post exposure interval control logic. For instance, the unique signal may be used to enable a flash-timing network having a time constant corresponding with the light generation time of a fired flashlamp. Such an arrangement provides an ideal flash-shutter synchronization technique. Additionally, the unique output signal condition may be used for selectively disabling a light-sensing network within the camera. With such an arrangement, the camera may automatically select a more desirable ambient illuminational control under conditions of very high scene brightness.

Another feature of the flash control of the subject camera resides in the use of a very short electromagnetically derived pulse to actuate the firing circuit to effect the ignition of a flashlamp. With such actuation, difficulties otherwise encountered in switch bounce conditions and the like are obviated. Such synchronization switch instability might otherwise lead to an unwanted sequential firing of flashlamps coupled within the sequencing circuit.

For some photographic applications, it may be found desirable to operate the subject automatic camera in nal condition then is utilized by the control system of different than that of a flashlamp when ignited. As a consequence, this necessary condition to terminate an exposureinterval may not be available. Further, sequencing circuits generally utilize solid state electronic components to carry out individual switching of lamps. Should such electronic switch be coupled through an inductive load as. might be present with an electronic flash adapter, the desired pulse actuation technique may not be capable of sustaining sufficient switching current flow to effect an electronic flash firing. Further, where inductive devices are utilized for firing an electronic flash,'the inductive fly-back pulse generated from said firing may injure the miniaturized circuit components of the camera.

SUMMARY The present invention is addressed to an electronic flash arrangement and method for the use thereof with a photographic camera of a variety having a flashlamp circuit incorporating lamp ignition monitoring capabilities. Representing an adapter technique, the invention provides an impedance having an impedance characteristic corresponding with the predetermined impedance characteristic of the flashlamps otherwise fired by the flash firing circuit. Additionally, a switching arrangement is provided which serves to fire the electronic flash in response to the actuation of the switching components of the flash firing circuit; Where the control circuit of the camera in which the flash firing circuit is contained is susceptible to spurious signals or the like occasioned with the firing of the electronic flash, the switching thereof may be carried out in electrical isolation from the switching operation of the flash firing circuit-In one embodiment, the invention utilizes an electromagnetic actuator to fire an electronic flash in response to synchronizingactuation of the flashlamp firing circuit. A requisite signal output condition of the flash firing circuit is retained through the use of a select impedance in conjunction with the electromagnetic actuator. This impedance is selected having a value corresponding with the impedance values of flashlamps otherwise fired by the circuit. The use of this impedance within the circuit also permits the switching elements of an electronic flashlamp firing circuit to draw adequate current levels to permit conduction for requisite intervals of energization.

In one version of the invention, diode means are incorporated with the winding of the electromagnetic ac- I pulse source. A monitor arrangement is incorporated with the circuit including a current detecting arrangement responsive to the exhibited impedance values of the flashlamps for deriving a select output condition used for control purposes. The adapter incorporates means connectable with the output terminals for acti; vating another source of illumination such as an electronic flash'unit. A switch. arrangement is provided which is actuable to activate the other source of illumination and this switch is, in turn, actuable by electromagnetic means which may be presentin the form of a relay. Additionally, an impedance is provided with the electromagnetic element of the, relay and this impedance is selected having a value corresponding with the impedance values of the flashlamps utilized by the monitoring function of the firing circuit. Preferably, this impedance is present as a resistor coupled in parallel with the winding or electromagnetic portion of the noted relay; To protect the contacts of the noted switch arrangement of the electronic flash unit, an electronic switch, such as a gate controlled thyristor device may be coupled'in parallel therewith and gated in response to closure of the noted switch contacts. Such an arrangement serves to preserve the contacts from undue deterioration Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter. 1 The'invention accordingly comprises the apparatus, method and system possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure. For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed'description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION referenced application for U.S. Pat., Ser. No. 246,891.

This camerais configured to operate substantially alternately in a flash illuminational mode and in an ambient illuminational mode, exposure regulation having a different technical basis for each suchmode.

Referring to FIG. 1, a block diagram showing the basic features for this two-mode control is illustrated. For instance, the exposure mechanism of the camera, as depicted at block 10, is preferably present as a dualbladed shutter device which is actuated from a tractive electromagnetic drive system as illustrated at block 12. Electromagnetic drive 12 and shutter or exposure mechanism 10 are mechanically associated as depicted by dashed line 11-, such that upon energization of a solenoid, the blades of mechanism 10 are caused to close to block the optical path of the camera. During an initial such blockage in the course of a photographic cycle, the optical path of the camera is converted from a viewing and focusing operation to one permitting the exposure of a film unit. The initial closure of the exposure mechanism blades 10 through actuation of an electromagnetic drive 12 is carried out by a cycle controlfunction 14 which is connected along input 16 to drive 12. During the optical path conversion, cycle control function 14, acting through line 18, operates an inhibit function 20 in a manner temporarily disabling a light-sensitive control circuit shown at 22. Functional connection between inhibit function 20 and circuit 22 is shown by line 24. Y

When exposure mechanism 10 has fully blockedthe noted optical path, cycle control 14 signals inhibit function 20 to enable light-sensitive control circuit 22 while, simultaneously, signaling electromagnetic drive 12 from line 16 in a manner de-energizing the noted solenoid. The latter de-energization permits exposure mechanism 10 to gradually unblock the optical path of the camera. Light-sensitive control circuit 22 monitors this gradual opening of the optical path as well as the a flash-firing circuit utilized with the control arrangement described in connection with FIG. 1;

FIG. 3 is a partial circuit diagram showing, in more detail, certain of the components of the circuit of FIG. 2;

FIG. 4 is a schematic diagram of an adapter arrangement according to the invention;

FIG. 5 shows another adapter arrangement which may be utilized in conjunctionwith a solid state flash firing circuit described in connection with FIGS. l-3;

FIG. 6 shows still another adapter arrangement which may be utilized in conjunction with a flash firing circuit described in connection with FIGS. 1-3; and

FIG. 7 is a front elevational view of a packaged adapter unit, the exposure housing of a camera and an electronic flash device. I

levels of brightness of the scene being photographed and, when an appropriate exposure value has been derived, the system signals a trigger-function 26 from along line 28 to effect the termination of this ambient mode exposure. This signal is presented along line 30 to electromagnetic drive 12. Drive 12, in turn, causes exposure mechanism 10 to rapidly block the optical path and terminate an exposure. Operating under the influence of cycle control 14 through line 16, electromagnetic drive 12 retains this optical path blocking posture at exposure mechanism 10 until such time as post exposurefilm processing operations and the like are carried out. When these operations have been completed, control 14 de-energizes electromagnetic drive 12 and resets the entire system for a next succeeding photographic cycle. Typical of the light-sensitive control circuits which may be used at block 22 is that described in a U.S. Pat. No. 3,620,143, by J. P. Burgarella, while the operation of such a light detecting arrangement in conjunction with an exposure control system is described in a U.S. Pat. No. 3,641,891, by the same inventor. Inhibit function 20 is preferably in the form of an electronic switch which serves to activate or de-activate control circuit 22. The inhibit function 20 is described in a copending application for United States patent by EJK. Shenk entitled Exposure Control System'lncorporating Solid State Switching to Enable a Light-Sensitive Network Ser. No. 213,289, filed on Dec. 29, 1971, and assigned in common herewith.

When the subject camera is operated in a flash operational mode, a packaged multiflashlamp array is attached thereto in a manner orienting the flashlamps of the array in a direction to illuminate a scene being photographed. With such mounting, cycle control function 14 is automatically adjusted to carry out a flash mode cycle. As is described in detail in the noted application for U.S. Pat., Ser. No. 246,891 during a flash operational mode, cycle control 14, operatingthrough line 16, activates electromagnetic drive 12 to cause exposure mechanism to block the optical path of the camera. As in the case for ambient mode operation, exposure mechanism 10 achieves and retains this optical blocking status until such time as the optical path is converted to an exposure orientation.

When exposure mechanism 10 has blocked the optical path, cycle control 14, acting from along line 32, also activates a follow-focus actuator 34. As is described in a copending application for United States patent by V. K. Eloranta and E.,I(. Shenk, entitled Focus Responsive Exposure Control System ,Ser. No. 135,211,flled Apr. 19, 1971 and in application for US. Pat., Ser. No. 168,671 by L. M. Douglas, entitled Apparatus and System for Flash Photography filed Aug.

7 3, 1971 both said applications being assigned in common herewith, such follow-focus systems operate in accordance with the level of illumination from a flash source which is anticipated at a subject being photographed. To anticipate these levels, the follow-focus actuator systems utilize an approach based upon an application of the inverse square law for light energy propagation. Under this law, the light energy available from a given source is considered to vary inversely with the squarefof the distance from that source. The followfocus technique utilizes the approach to automatically adjust aperture through a coupling between the exposure mechanism 10 and the focusing system of the camera. In the instant arrangement, a tractive electromagv netic device in the form of a solenoid is utilized to arrest the movement of the blades of exposure mechanism 10 as they are released by drive 12 for movement from a fully closed position toward a fully open position. The mechanical interaction between follow-focus actuator function 34 and exposure mechanism 10 is depicted by dashed line 36. As is described in the abovenoted application Ser. No. 246,891, following an appropriate delay interval to permit proper arresting and capture of the blades of exposure mechanism 10 by follow-focus actuator arrangement 34, the solenoid within the latter is de-energized to inductively derive a flash firing pulse. This pulse is introduced through appropriate interconnection depicted by line 38 to a flash firing circuit depicted at 40. Responding to this pulse input from line 38, firing circuit 40 selects an appropriate flashlamp within the camera'mounted flash array as at 42, and operating through flash output terminals 44 and 46, ignites a flashlamp to illuminate the scene being photographed.

Should flashlamp illumination be successful, the illuminating lamp will exhibit a predetermined value of resistive impedance which, in turn, is witnessed by a sensing and monitoring function within firing circuit 40.

This monitoring'function then derives a unique output signal which is presented along line 48. When thus presented on line 48, the unique signal, acting from line 50, activates a fixed delay function 52, the unique signal condition at line 48 also acts upon inhibit function 20 to disablelight-sensitive control circuit 22. Following a predetermined interval of time selected in correspondence with the time required for the ignited flashlamp to generate all available light, fixed delay 52 signals trigger function 26 from line 54 to carry out an exposure terminating function. Accordingly, trigger 26, signaling from along line 30, activates electromagnetic drive 12 to energize the noted shutter drive solenoid and, operating through mechanical linkage 11, causes exposure mechanism 10 to block the optical path of the camera. This optical path blocking orientation is retained until such time in film processing and optical path re-orientation procedures are carried out. As in the case of the ambient illuminational cycle, cycle control 14 then causes the system to shut down or assume a standby status in preparation for a next succeeding photographic cycle.

. Looking to FIG. 2, a schematic representation of a flash firing circuit as described at is presented. In the figure, a plurality of flashlamps 60a 600 are shown connected, respectively, to the terminals 62a 62c of three lamp circuit lines 64a 64c. Circuit lines 64a 640 are connected in parallel circuit relationship to one another between power or bus leads 66 and 68. Leads 66 and 68, in turn, are connected, respectively, with a current monitoring as well as sensing function 70 and a flashlamp switching network 72. Monitor function 70, as well as network 72 are energized from a power supply depicted functionally at 74. Each lamp circuit line 64a 640 also includes a switching function shown, respectively, as SCRs 76a 76c. The gate electrodes of SCRs 76a e 760, respectively, are connected through lines 78a 780 to switching network 72. When actuated from a pulse generator as at 80, flashlamp switching network 72 sequentially gates a select one of SCRs 76a 760. When so gated, the selected SCR is commutated to permit the passageof igniting current through the flashlamp with which it is associated. Pulse network 72 and latch 86 is provided. In the figure,

generator function 80 will be recognized as representing the solenoid feature of tion 34.

As a select one of the flashlamps a 600 is ignited, a voltage drop will be witnessed across a resistor as at 82. Resistor 82 is connected within line 84 between lead 66 and current monitor 70. When such voltage drop is so witnessed or sensed, monitor function signals a latch network 86 to establish a unique signal condition such as that described at line 48 in FIG. 1. This output from flash 86 is represented in FIG. 2 at 88. Should a flashlamp 62a 62c fail to ignite, monitor 70 will not witness'a voltage drop at resistor 82 and no signal will be'passed to latching network 86. Accordingly, output 88 will not evidence its requisite unique output signal condition. Under such circumstance, neither the fixed delay described at 52 nor light-sensitive control circuit inhibition as at 20 will take place and the camera progesses through a form of ambient mode photographic cycle.

Referring to FIG. 3, a more detailed representation I for current monitor and sensing function 70, switching where appropriate, identical numeration is retained for follow-focus actuator func- 1 networks 94 and 96. Network 94 is connected through line 98 to line 64a at the anode side of SCR 76a and, additionally, is coupled to gating line 78b of SCR 76b. Similarly, logic network 96 is connected through line 100 to lamp circuit line 64b at the anode side of SCR 76b and to gating line 780 of SCR 760. Functions 94 and 96 serve to detect the previous firing of a flashlamp, for instance, at 60a and cause the circuit to select a next flashlamp, i.e., 60b by relaying a firing or gating pulse to the appropriate SCR thereof, i.e., 76b. Typical sequencelogic techniques as provided by functions 94 and 96 aredescribed in the noted U.S. Pat. No. 3,618,492.

} The firing circuit being energized from lines 68 and 92, a pulse of short duration, for instance about microseconds is generated from follow-focus actuator 34 as depicted at function block 102. This pulse is directed along line 104 and through a level detecting zener diode 106 to the emitter terminal of a PNP transistor 0,. The base of transistor O is connected through line 108 to power line 92, .while its collector electrode is coupled with line'1l0. Line 110, in turn, is connected through line 112 and a limiting resistor 114 to the base of an NPN transistor Q Bypass resistor 1.16 is connected within line 118 between ground or power lead 68 and line 112 intermediate resistor 114 and the base of transistor 0,. The collector of transistor Q is connected through line 120 to power lead 92, while its emmitter is connected with gate line 78a of SCR 76a. With ward biasing of transistor Q ,line 130 is energized and a basic reference voltage is established through diode 134. This reference voltage is further refined by'a voltage dividing network including resistors 136 and 138 connected within line 140 between the cathode side of diode 134 and powerline 92. The refined reference voltage level is tapped by a line 142 connected intermediate resistors 136 and 138 and extending to the emitthe arrangement shown, in the presence of a short duration pulse at line 104, transistor Q, is forward biased into conduction for a correspondingly short interval to energize lines 110 and 112 and, inconsequence, forward bias the base-emitter junction of transistor Q Transistor O simultaneously activates line 120 from power lead 92 to impose a short duration gating current irito gate line 78a of SCR 76a. Thus gated, SCR 76a is turned on to ignite the filament of flashlamp 60a. SCR 761: will remain on until commutated off due to decay occurring in line 64a occasioned with the destruction of the igniting filament within flashlamp 60a.

With the next succeeding actuation of the firing circuit,

SCR-76a will be gated on, howevensustaining current will be derived from line 98of sequence logicl network 94. Network 94, in turn, will supply gating current through line 78b to SCR 76b. Accordingly, for this actuation of the firing circuit-flashlamp 60b will ,be ignited. The next succeedingflash'cycle will activate sequence logic circuit 96 through line 100 in identical fashion to effect the ignition of the final flashlamp 600 of the series. Of course, several additional flashlamps may be arranged within this form of firing circuit.

With the forward biasing of transistor Q, for the brief interval occasioned from the pulse at'line 104, an NPN ter terminal of a PNP'transistor Q.,. The collector of transistor 0., is connected to a gate lead 144, while its base is connected to a common line 146. The voltage level witnessed at line 146 is insufficient to effect a forward biasing of the base-emitter junction of transistor Q4. Line 146 is also connected to the base of another PNP transistor Q theemitter of which is connected through linevl48 to one side of resistor 82 within line 90. The collector of transistor O is connected through line 150, line 152 and resistor 154 to line 130. Note, in view of a forwardbiasing of transistor Q the voltage at line 146 follows the voltage variation at resistor 82. With the arrangement, a form of comparison network is provided. For instance, assuming that v a selected flashlamp a 600 has been successfully ignited, current passage through sensing resistor 82 will derive. a

voltage drop which is witnessed at'common line 146 inasmuch as transistors Q, and Q are selected to remain conductive throughout the duration of the actuating pulse introducedfrom line 104. This witnessed voltage drop at line 146 serves to enhance the biasing of transistor Q, and, as a consequence, transistor 0, commences to conduct and, thereby activate gate line 144. Line 144, in turn, gates on an'SCR 156 connected within line 128. Thus gated, SCR 156 commences to conduct through resistor 158 and. will remain conducting until sustaining current from power lines 92 and 68 is abated. Line 128 alsois connected from theanode side of SCR 156 through line 160 and resistor 162 to the base of PNP transistor Q The emitter of transistor Q, is connected through line 164 to power line 92,

while its collector is connected through resistor 166 and line 168 to line 68. As SCR 156 continues to conduct, transistor 0,, is forwardbiased. The resultant energized state of line 168 and the voltage level in evidence thereat is introduced to output line 88 which, in turn, provides the unique signal condition required to operate fixed delay 52 as well as inhibit function 20.

Should a selected flashlamp 622a 62c fail to ignite, no appreciable igniting current will pass through sensing resistor 82, and no voltage drop will be witnessed at common line 146. As a consequence, transistor Q, is not forward biasedand no gating signal is applied through gate line 144 to turn on SCR 156. Inasmuch as SCR 156 does not conduct, transistor Q, is not forward transistor 0;, also is forward biased. The baseof tr'an'sis- I 7 sistor 132 and diode 134 to power line 92. With the forbiased and the unique signal condition described earlier will not bein evidence at output 88. t

Theoperational description of the circuit of FIG. 3 reveals that the very short pulse supplied from followfocus actuator function 102, for instance, '10 microseconds requires that the current to maintain conduction through all of the noted SCRs must reach' a sustaining level within the period of thepulse itself. While such sustaining levels are readily achieved with the resistive igniting filament arrangement of typical flashlamps, such is not'the case where inductive loads or the'like are's'ubstituted for these igniting filaments. Where such inductive load is substituted, the current buildup characteristic at the firing SCRs as at 76a 76c would .be

I pear to permit the camera to complete its photographic cycle.

Referring to FIG. 4, an adapter arrangement for actuating an electronic flash 178 orthe like from a flash: lamp firing circuit as at 40 is disclosed generally at 180. Any one of the contact terminals as earlier described at 62a 620 may be tapped for interconnecting circuit 40 with adapter 180. For instance, terminals identified at 182 and 184 are shown. Corresponding leads 186 and 188 are provided in adapter 180 for purposes of interconnecting the winding 190 of a reed-type relay or the like across contacts 182 and 184. Winding 190 of the relay serves to cause a closing of the contacts of a switch designated l92'when energized. The electrically isolated association between winding 190 and switch 192 is depicted by dashed line 194, As discussed earlier, winding 190 represents an inductive load to. the flashlamp firing circuit 40. Without more, this load would hinder c'urrentbuild-up through lamp circuit 64a 640 to an extent preventing SCRs 76a 760 from conducting at a sustaining current level prior to the removal of gating current at line 78a 78c occasioned with the end of the actuating pulse. To correct for this inductive characteristic, an impedance in the form of a fixed resistor 196 is coupled between lines 186 and Y188 in parallel circuit relationship with winding 190.

Additionally, a diode as at 198 is similarly connected in parallel with winding 190. With the arrangement shown, when abrief igniting signal energizes contacts 182 and 184, winding 190 commences to be energized to close switch 192. To permit the flash firing circuit 40 to operate properly, resistor 196 isselected having an impedance characteristic closely proximate that of flashlamps 60a 600. Accordingly, circuit 40 sees a successful ignition of flashlamp, transistor 0, conducts and latching SCR 156 is commutated into conduction (FIG. 3). As a consequence, the requisite unique signal condition is present at output line 88. Inasmuch as during the energization of winding 190 a fly-back pulse may be generated, diode 198 is connected between lines 186 and 188 in parallel circuit relationship therewith. Thus positioned, diode 198 serves to dissipate any fly-back pulses or the like which may be generated.

Inasmuch as switch 192 may be of somewhat delicate structure, it is desirable that it not be called upon to operate under the relatively high currentconditions that may be encountered with electronic flash units as at 178. To protect the contacts at switch 192, therefore, a switching SCR 199 is connected within line 200 be tween input lines 202 and 204 and in parallel with switch 192. The gate 206 of SCR 199 is connected intermediate a pair of voltage dividing resistors 206 and 208 connected, in turn, with switch 192 in line 210. With the arrangement shown, as relay contacts or the contacts of a switch 192 are closed upon energization of winding 190, gate 206 of SCR 199 is activated to commutate it on substantially simultaneously with the closure of switch 192. As a result, SCR 199 assumes substantially all of the current load occasioned with the firing of electronic flash unit 178.

Referring to FIG. 5, another adapter arrangement for use with flash firing circuit 40 is shown generally at 210. As in the case of FIG. 4, any pair of the terminals 62a 62c of firing circuit 40 may be utilized or tapped for purposes of electrical connection with an electronic flash 212 or the like. Such contacts are depicted at 214 and 216. Adapter arrangement 210 includes a load resistor 218 having an impedance value selected for simulating the impedance value of the igniting filament of a flashlamp 60a 60c. Accordingly, resistor 218 operates in identical fashion as resistor 196 described in connection with FIG. 4. More particularly, the resistor permits sustaining current to flow through the appropriate switching SCR 76a 76b as well permitting a latching function to be carried out by SCR 156. Resistor 218 is connected between leads 220 and 222 which, respectively, are coupled with terminals 214 and 216. A drain limiting resistor 224 is connected in line 220 and serves the function of limiting a drain from firing circuit 40. Line 220 also is connected to the base of an NPN transistor Q The emitter of transistor O is connected along line 226 to line 222 while its collector is connected through line 228 to a winding 230 of a relay, for instance, of a reed variety. Winding 230, in turn, is connected to a separate power supply present as a battery 232. As is apparent, upon energization of adapter arrangement 210 from contacts 214 and 216, transistor Q is forward biased to energize winding 230 from battery 232. As a consequence, relay contacts 234 are closed to fire electronic flash 212. Note that contacts 234 are present inan actuating output line 236 extending from electronic flash 212. A resistor 238 is positioned between lines 214 and 216 to assure that transistor Q is biased "of until utilized for switching purposes. A diode 242present within line 244 is connected across winding 228. As in the embodiment of FIG. 4, this diode serves to suppress excessive transients and the like which may be generated with the deenergization of winding 228. With the self-powered arrangement shown in FIG. 5, no undue po'wer drains are occasioned in operating the additional circuitry provided within the adapter arrangement. Where the general power supply of the camera utilizing the control system is limited, such additional power supply may be of some value.

Referring to FIG. 6, another adapter arrangement for use with flash firing circuit 40 is shown generally at 250. As in the embodiments of FIGS. 4 and 5, any pair of terminals 62a 62c of firing circuit 40 may be utilized or tapped for the purposes of electrical connection with an electronic flash 252. Such contacts are depicted at 254 and 256. The embodiment of FIG. 6 differs from that of the earlier described embodiments inasmuch as electronic flash device 252 is switched or fired without the electrical isolation feature of those embodiments. Where the integrated circuitry of a camera is sufficiently immune from damage due to voltage excursions or the like which might have been generated from an electronic flash device, such an arrangement is available. Accordingly, the actuating switch output of electronic flash device 252 is coupled to adapter arrangement 250 at contacts 258 and 260.

As in the earlier embodiments, adapter arrangement 250 includes a load resistor 262 having an impedance value or characteristic selected for simulating the impedance values or characteristics of the igniting filament of a flashlamp a 600. Accordingly, resistor through the appropriate switching SCRs 76a 7612 as well as permitting a latching function to be carried out by SCR- 156 (FIG. 3). Resistor 262 is connected between leads 264 and 266 which, respectively, are coupled with terminals 254 and 256. Coupled in parallel with resistor 262 is a divider network 268 formed of resistors 270 and 272. The function of network 268 is to develop a signal of appropriate level at line 274 for gating a high voltage SCR 276 to an on condition. The anode side of .SCR 276 is connected through line 278 to contact 258, while itscathode is connected along line 280-to line 266. Line 266 may represent connection with a common contact terminal of flash firing circuit 40.

With the arrangement shown, upon energization of adapter arrangement 250 from contacts 254 and 256, SCR 276 is gated from line 274 to'close the circuit across contacts 258 and 260. Electronic flash device- -252 is fired or switched on and resistor 262 serves the function of causing flash-firing circuit 40 to see a successfulignition of a flashlamp. i a Looking to FIG. 7, an exploded'view showing a typical electronic flash device at 290, an adapter arrangementin packaged form at 292 and the exposure housing portion 294 of a photographic camera as described in the notedapplication for US. Pat, Ser. No. 246,891 is revealed. Exposure housing 294 generally incorporates a cover portion 296, a lens mounting 298, an entrance window 300 for providing light responsive exposure control,-a start button 302, a focusing knob 304 and a trim wheel 306.;A flash array mounting structure 308 is positioned upon the top of housing 296 and is designed to receive and support a blade-type support and electrical contact device of a linear flash array. This blade support is shown at 310 extending downwardly from adapter unit 292. The terminals for a typical flash array areformed by printed circuitry technique upon support 310 and include a common terminal 312 as well as a switch'actuating surface 314. As discussed earlier, surface 314 serves to cause the control system of a camera to carry out. a flash photographic cycle. Of

course, such switching or other adjustment of the control system is carried out in conjunction with each of the disclosed embodiments, dependent upon the camera structure or design involved. The remaining terminals upon the support 310 would otherwise lead to indi- I vldual flashlamps but are connected incommon with a lead as at 264 in FIG. 6, lead 220 in FIG. 5 or lead 186 in FIG. 4. Common terminal 312, of course, corresponds with'lead 266 in FIG. 6 and its'counterpart in FIGS. 4 and 5. The switching output of adapter 292 is provided at a coaxial contact member configured to couple with a mating end of a switching cable 316 of flash unit 290, a supporting blade as at 310-merely extending from the bottom of housing 320.

Since certain changes may be made in the abovedescribed system and apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the description thereof as shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. Apparatus for use with a camera having a photographic exposure control'system of a variety operative when selectively activated to ignite a replaceable flashlamp exhibiting a predetermined impedance characteristic when so ignited, said system including means responsive to said exhibited impedance characteristic for performing an operational function, comprising:

a support;

electrical input terminal means on said support;

- electrical output terminal means on said support;

means connected ,to said support for attaching said apparatus. to the camera with its said electrical input terminalmeans inelectrical communication with the camera's photographic exposure control system; means formed on said support for mounting another source of artificial illumination, not exhibiting said .predetermined impedance characteristic when ignited, in electrical communication with said output terminal means; switching means connected between said electrical input and output terminal means and responsive to said selective activation for effecting theenergiza-' tion of theother source of artificial illumination; and i I impedance means connected to said electrical input terminal means, said impedance means being selected so that said apparatus exhibits said predetermined impedance characteristic to said electrical input terminal means when the other source of illumination is energized responsive to said selective activation. 2. The apparatus of claim 1 in which said impedance means is present as a resistor having a resistivity value substantially equivalent to the value of resistivity exhibited by said flashlamp when ignited.

' rating a'flashlamp firing circuit having switching net'- adapter 292 can be formed integrally within electronic work means connectable with flashlamps exhibiting predetermined impedance characteristics when ignited in response to actuation of said switching network means and including monitor means responsive to said exhibited impedance characteristic for deriving a select output condition, apparatus comprising:

impedance means selectively connectable with said switching network means and exhibiting said predetermined impedance characteristic in the presence of said'actuation thereof; and

switching means which includes said impedance means and is responsive to said switching network means actuation for effecting the energization of a source of artificial illumination other than said flashlamps.

5. The invention defined in claim 4 in which said impedance means is present as a resistor having a resistivity value substantially equivalent to the value of resistivity exhibited by said flashlamp when ignited.

6. The invention-defined in claim 4 in whichsaid switching means is present in solid state configuration and is gatable to effect said energization of said source of artificial illumination other than said flashlamps.

7. The invention defined in claim 4 in which said switching means is present in solid state configuration and includes a gating input responsive to said switching network actuation for effecting the energization of a source of artificial illumination other than said flashlamps.

8. Apparatus for firing an electronic flash device with an exposure control system of the variety incorporating a flashlamp firing circuit having switching network .means connectable with flashlamps exhibiting predetermined impedance characteristics when ignited in response to the application of a voltage by said switching network means and including monitor means responsive to said exhibited impedance characteristic for deriving a select output condition, said apparatus comprising:

an impedance having said predetermined impedance characteristic, means for connecting said impedance to said switching network means; and circuit means operatively connected to said impedance for firing said electronic flash device in response to voltage applied by said switching network means.

9. The apparatus of claim 8 in which said circuit means areelectrically isolated from said switching network means;

10. An adapter for interconnecting a photographic control system, of the type having first terminals adapted to be electrically energized to ignite a flashlamp and operative in a cycle conditioned by the presence or absence of a first'impedance across said terminals when said terminals are excited, with a source of illumination having second terminals and exhibiting a secondimpedance, said source being responsive to a predetermined signal applied to said second terminals to produce a flash of light; said adapter comprising: circuit means having input terminals adapted to be connected to saidfirst terminals, output terminals adapted to be connected to said second'terminals, an input impedance between said input terminals equal to said first impedance, and means responsive to the electrical energization of said input terminals including said impedance for applying said predetermined signal to said output terminals.

11. A strobe adapter for interconnecting a flash camera having output terminals for producing a flashlamp igniting signal to a strobe unit having control terminals adapted to receive a trigger signal, comprising a pair of input terminals adapted to be connected to the flashlamp igniting terminals of the camera, output terminals adapted to be connected to the control terminals of the strobe unit, impedance means simulating a flashlamp connected between said input terminals, switching means connected to said output terminals and responsive to an applied signalto produce a trigger signal across said output terminals, and means responsive to a flashlamp igniting signal applied to said input terminals including said impedance for applying. a signal to said switching means.

12. An electronic flash assembly for use witha photographic exposure control system of a variety having terminals energizable to ignite a flashlamp exhibiting a predetermined impedance characteristic when so ignited, comprising:

illumination generating means operative by switching actuation to generate, by gas discharge technique,

an illuminational output;

impedance means having an impedance characteristic corresponding with said predetermined impedance characteristic and connectable in seriescircuit relationship with said exposure control system terminals; and

switching means operatively connected to said impedance means and responsive to said terminal energization when said impedance means is connected with said terminals for effecting said switching actuation of said illumination generating means. w

13. The electronic flash assembly of claim 12 in which said switching means is present in solid state configuration and is gatable to effect said switching actuation of said illumination generating means.

14. The electronic flash assembly of claim 12 in which said switching means is present in solid state configuration and includes a gating input selectively connectable with said terminals, said switching means being gatable from said input upon the occurrence of said energization of said terminals.

15. The electronic flash assembly of claim 12 in which said switching means includes:

a switch actuable to carry out said generating means switching actuation; and

electromagnetic actuator means energizable in response to said terminal energization for actuating said switch.

16. An electronic flash unit for use with a flash camera having output terminals for producing a flashlamp igniting signal, comprising electronic flash discharge means having control terminals adapted toreceive a trigger signal and discharge circuit means coupled to said control terminals for producing a flash of light in response to a trigger signal applied to said terminals, a pair of input terminals adapted to be connected to the flashlamp igniting terminals of the camera, impedance means simulating a flashlamp connected between said input terminals, and trigger signal producing means responsive to a flashlamp igniting signal applied to said input terminals for applying a trigger signal to said control terminals;

17. The apparatus of claim 16, in which said impedance means comprises a resistor, and in which said trigger signal producing means comprises an electronic switch having actuating terminals connected to said input terminals and load terminals connected to said control terminals.

18. The apparatus of claim 17, in which said electronic switch is a controlled rectifier.

19. The apparatus of claim 17, in which said electronic switch is a transistor.

20. The apparatus of claim 16, in which said trigger signal producing means is a relay having a winding connected to said input terminals and contacts connected to said control terminals. 5 

1. Apparatus for use with a camera having a photographic exposure control system of a variety operative when selectively activated to ignite a replaceable flashlamp exhibiting a predetermined impedance characteristic when so ignited, said system including means responsive to said exhibited impedance characteristic for performing an operational function, comprising: a support; electrical input terminal means on said support; electrical output terminal means on said support; means connected to said support for attaching said apparatus to the camera with its said electrical input terminal means in electrical communication with the camera''s photographic exposure control system; means formed on said support for mounting another source of artificial illumination, not exhibiting said predetermined impedance characteristic when ignited, in electrical communication with said output terminal means; switching means connected between said electrical input and output terminal means and responsive to said selective activation for effecting the energization of the other source of artificial illumination; and impedance means connected to said electrical input terminal means, said impedance means being selected so that said apparatus exhibits said predetermined impedance characteristic to said electrical input terminal means when the other source of illumination is energized responsive to said selective activation.
 2. The apparatus of claim 1 in which said impedance means is present as a resistor having a resistivity value substantially equivalent to the value of resistivity exhibited by said flashlamp when ignited.
 3. The apparatus of claim 1 in which said switching means is present in solid state configuration and is gatable to effect said energization of said source of artificial illumination not exhibiting said predetermined impedance characteristic.
 4. In an exposure control system of a variety incorporating a flashlamp firing circuit having switching network means connectable with flashlamps exhibiting predetermined impedance characteristics when ignited in response to actuation of said switching networK means and including monitor means responsive to said exhibited impedance characteristic for deriving a select output condition, apparatus comprising: impedance means selectively connectable with said switching network means and exhibiting said predetermined impedance characteristic in the presence of said actuation thereof; and switching means which includes said impedance means and is responsive to said switching network means actuation for effecting the energization of a source of artificial illumination other than said flashlamps.
 5. The invention defined in claim 4 in which said impedance means is present as a resistor having a resistivity value substantially equivalent to the value of resistivity exhibited by said flashlamp when ignited.
 6. The invention defined in claim 4 in which said switching means is present in solid state configuration and is gatable to effect said energization of said source of artificial illumination other than said flashlamps.
 7. The invention defined in claim 4 in which said switching means is present in solid state configuration and includes a gating input responsive to said switching network actuation for effecting the energization of a source of artificial illumination other than said flashlamps.
 8. Apparatus for firing an electronic flash device with an exposure control system of the variety incorporating a flashlamp firing circuit having switching network means connectable with flashlamps exhibiting predetermined impedance characteristics when ignited in response to the application of a voltage by said switching network means and including monitor means responsive to said exhibited impedance characteristic for deriving a select output condition, said apparatus comprising: an impedance having said predetermined impedance characteristic, means for connecting said impedance to said switching network means; and circuit means operatively connected to said impedance for firing said electronic flash device in response to voltage applied by said switching network means.
 9. The apparatus of claim 8 in which said circuit means are electrically isolated from said switching network means.
 10. An adapter for interconnecting a photographic control system, of the type having first terminals adapted to be electrically energized to ignite a flashlamp and operative in a cycle conditioned by the presence or absence of a first impedance across said terminals when said terminals are excited, with a source of illumination having second terminals and exhibiting a second impedance, said source being responsive to a predetermined signal applied to said second terminals to produce a flash of light; said adapter comprising: circuit means having input terminals adapted to be connected to said first terminals, output terminals adapted to be connected to said second terminals, an input impedance between said input terminals equal to said first impedance, and means responsive to the electrical energization of said input terminals including said impedance for applying said predetermined signal to said output terminals.
 11. A strobe adapter for interconnecting a flash camera having output terminals for producing a flashlamp igniting signal to a strobe unit having control terminals adapted to receive a trigger signal, comprising a pair of input terminals adapted to be connected to the flashlamp igniting terminals of the camera, output terminals adapted to be connected to the control terminals of the strobe unit, impedance means simulating a flashlamp connected between said input terminals, switching means connected to said output terminals and responsive to an applied signal to produce a trigger signal across said output terminals, and means responsive to a flashlamp igniting signal applied to said input terminals including said impedance for applying a signal to said switching means.
 12. An electronic flash assembly for use with a photographic exposure control system of a variety having terminals energizable to Ignite a flashlamp exhibiting a predetermined impedance characteristic when so ignited, comprising: illumination generating means operative by switching actuation to generate, by gas discharge technique, an illuminational output; impedance means having an impedance characteristic corresponding with said predetermined impedance characteristic and connectable in series circuit relationship with said exposure control system terminals; and switching means operatively connected to said impedance means and responsive to said terminal energization when said impedance means is connected with said terminals for effecting said switching actuation of said illumination generating means.
 13. The electronic flash assembly of claim 12 in which said switching means is present in solid state configuration and is gatable to effect said switching actuation of said illumination generating means.
 14. The electronic flash assembly of claim 12 in which said switching means is present in solid state configuration and includes a gating input selectively connectable with said terminals, said switching means being gatable from said input upon the occurrence of said energization of said terminals.
 15. The electronic flash assembly of claim 12 in which said switching means includes: a switch actuable to carry out said generating means switching actuation; and electromagnetic actuator means energizable in response to said terminal energization for actuating said switch.
 16. An electronic flash unit for use with a flash camera having output terminals for producing a flashlamp igniting signal, comprising electronic flash discharge means having control terminals adapted to receive a trigger signal and discharge circuit means coupled to said control terminals for producing a flash of light in response to a trigger signal applied to said terminals, a pair of input terminals adapted to be connected to the flashlamp igniting terminals of the camera, impedance means simulating a flashlamp connected between said input terminals, and trigger signal producing means responsive to a flashlamp igniting signal applied to said input terminals for applying a trigger signal to said control terminals.
 17. The apparatus of claim 16, in which said impedance means comprises a resistor, and in which said trigger signal producing means comprises an electronic switch having actuating terminals connected to said input terminals and load terminals connected to said control terminals.
 18. The apparatus of claim 17, in which said electronic switch is a controlled rectifier.
 19. The apparatus of claim 17, in which said electronic switch is a transistor.
 20. The apparatus of claim 16, in which said trigger signal producing means is a relay having a winding connected to said input terminals and contacts connected to said control terminals. 